I. Field of the Invention
The present invention relates generally to vehicle-mounted concrete mixing and dispensing systems and, more particularly, to on-board auxiliary fluid supply systems employed to supply water for washout or adding water and/or chemical additive to a concrete mix. Specifically, the present invention relates to a lightweight two-chamber split auxiliary tank for a fluid supply system that enables the addition of water and/or chemical additives from a compact two-chamber on-board supply.
II. Related Art
Transit concrete mixing trucks, sometimes referred to as ready-mix trucks, have long been in use. They are equipped with large chassis-mounted rotatable mixing drums for mixing and dispensing a quantity of concrete. The drums typically are mounted on an incline and have an opening in the upper end for receiving ingredients to be mixed and discharging mixed concrete products. Loading is accomplished through a charge hopper which extends a distance into the opening of the drum. The drum is further provided with internal helical flights or fins extending around its internal surface which act to propel material forward and mix the concrete ingredients when the drum is caused to rotate in one direction and cause the mixed concrete to be discharged from the opening when the rotation of the drum is reversed. The upper portion of the drum includes a ring and roller system for drum support and rotation that is carried by a heavy pedestal support assembly.
The trucks are often further equipped with auxiliary water supply systems including tanks carried on the truck. These systems are necessary for several reasons. After mixing and discharge, the mixing drums retain an amount of residual concrete on the mixing fins and inner drum surface and discharge chutes which needs to be periodically washed out to prevent it from curing and hardening in situ inside the drum and on external chutes. Therefore, it has become part of the operating routine to wash the interior of the drum and the discharge chutes one or more times per day. In addition, it is routinely necessary to add additional makeup water and/or amounts of chemical additives to concrete batches mixed in the drum prior to discharge.
In conjunction with the use of makeup or washout water on transit concrete mixing trucks, it has further become a common practice to provide a water supply on the vehicle. The auxiliary water supply has included a water tank that has been typically pressurized to 50 psi or higher by a supply of air from a compressor carried on the truck. This, in turn, supplies water under pressure for washout or other uses through hoses and a valving system in a well-known manner. Alternatively, more recently, the pressurized system may be replaced by a pump assembly which eliminates the need to pressurize the tank. Such a system is illustrated and described in co-pending application Ser. No. 11/355,049, entitled Auxiliary Water Tank and Pump Assembly For a Vehicle, filed Feb. 15, 2006. That application is deemed incorporated herein by reference in its entirety for any purpose.
To date, auxiliary water tanks that have been used have been rather heavy metal structures which both are heavy and may add corrosion problems to the system. While aluminum tanks may reduce weight and corrosion problems, they remain relatively more expensive which is an additional drawback. In addition, with prior tanks it has been necessary to provide a separate facility to store and dispense chemical additives which are often necessary to be added to a mix at a job site.
Thus, there remains a need for an on-board auxiliary water/chemical additive supply and storage system that includes container that are relatively lightweight and inexpensive, which do not corrode and which can provide an easy-to-use, on-board supply of both water and chemical additives.